Diaphragm



Aug. 9, 1932. R. F. MALLINA DIAPHRAGM Filed Jan. 15. 1929 Patented Aug.9, 1932 UNITED STATES PATENT OFFICE RUDOLPH F. MALLINA, OF ATLANTICCITY, NEW JERSEY, ASSIGNOR, IBY MES NE AS- SIGNMENTS, TO RADIOCORPORATION OF AMERICA, OF NEW YORK, N. Y.,'A COR- JPORATION OF DELAWAREDIAPHRAGM Application filed January 15, 1929. Serial Io. 332,737.

My invention relates to a diaphragm of any desirable or suitable @size,shape or configuration and utilizable particularly for sound reproducingpurposes; my invention also relates to a method of constructing orforming a diaphragm.

In accordance with my invention, a diaphragm, as aforesaid, is providedwith integral corrugations extending in different directions and, moreparticularly, said corrugations are disposed or arranged in crosswiserelation.

tial y complete, integral corrugations and linear, integral corrugationsdistributed thereon in cross-wise relation.

Further in accordance with my invention, a shaped, corrugateddiaphragm-forming section or structure having a desired configuration isdisposed within and suitably attached to a similarly shaped structure tothereby produce a composite diaphragm, one of said shaped structures,ordinarily, having circumferentially complete corrugations distributedthereon and another of said shaped structures, ordinarily, having linearcorrugations distributed thereon.

My invention resides in the novel diaphragm and in the diaphragmassembling or producing method of the character hereinafter describedand claimed.

For an illustration of one of the forms my diaphragm may take and for anunderstanding of my method, reference is to be had to the accompanyingdrawing, in which:

Figure 1 is a vertical sectional view of a shaped structure or sectiondestined to form a part of a diaphragm.

Fig. 2 is a vertical sectional view-of a complemental diaphragm-formingstructure or section.

Fig. 3 is a vertical sectional view of the assembled diaphragm.

Fig. 4 is an elevational'vie'w of the section or structure shown in Fig.2.

Fig. 5 is a vertical sectional view, partly in elevation, of anassembled diaphragm and actuating magnetic mechanism therefor.

Diaphragms of the prior art and particularly those known as the conetype are customarily constructed of light weight material which has atendency to and often does vibrate in local regions to thereby causedistortion or other unnaturalness of the propagated sound waves. Ingeneral, my invention comprehends a diaphragm, so corrugated orotherwise strengthened, that it is largely or substantially entirelyinsensible to such formation of vibrations in local regions thereof.With such a diaphragm, the faithfulness of the sound reproduction isenhanced or increased to a degree not now existing in the prior artarrangements.

For one specific form of diaphragm which may be constructed inaccordance with my invention, reference is to be had to the drawing andparticularly Figs. 1 and 2 which show complemental structures orsections destined to form a single diaphragm. As shown, the structure orsection A of Fig. 1 is a substantial replica of the structure or sectionA1 of Fig. 2 with the exception that-the two sections are difierentlycorrugated and that the diametrical dimensions of the section A aresmaller than those of section A1.

In the example shown, both of the diaphragm-forming sections A and A1are frustro-conical and hollow, the section A having or comprising,preferably, a plurality of circular, circumferentially completec0rrugations 1 spaced from one another and the section, A1 usually,having a plurality of linear corrugations spaced from one another andangularly disposed with respect to the circular corrugations 1. Thecorrugations 1 extend well toward each end of the section A and thecorrugations 2 may extend throughout the entire length of the sectionA1. However, to prevent undue crowding, it is desirable that alternatecorrugations 2 be shortened as indicated in Fig. 2.

Referring to Fig. 3, the section A is shown as disposed within thesection A1 and in this position the two sections are suitably attachedor secured together so that, in effect, they form an integral vibratorystructure. For thus securing the sections A and A1 together there may beutilized any suitable cement, as one having a celluloid base, shellac,glue, or the like.

As shown in Fig. 3, the composite or assembled diaphragm carries or hassecured thereto various parts by which it may be incorporated in themagnetic and casing structure of diaphragm-actuating device or apparatusof a type well known to the art. As shown, the assembled diaphragm, atits smaller end carries a supporting member 3 of suitable insulatingmaterial, as stilf paper, upon Which is disposed a coil 4 comprising aplurality of convolutions of a suitable conductor traversed by currentwhich has been modulated or which varies in accordance with the sound tobe reproduced. The support 3 is cylindrical, hollow and usuallycomprises a transverse web or member 311 from which angularly extends aflange 3b, the latter being disposed between the sections A and A1 andbeing firmly and securely held in the position illustrated in Fig. 3after the aforesaid glue, cement, or the like, has hardened or set. Atthe opposite or larger end of theassembled diaphragm, the inner edge ofa ring-shaped member 5 of leather, fabric, or other suitable flexiblematerial, is received between the sections A and A1, said inner edge ofthe member 5 being held in the position illustrated in Fig. 3 the sameas is the flange 3b of support 3. At its outer edge, the member 5 hassuitably secured thereto rings or washers 6 of cardboard or the like.

Referring to Fig. 5, the composite dia phragm and associated equipmentis illustrated as mounted or disposed within the casing of a magneticdiaphragm-actuating device of a type well known to the art. As shown,this device comprises a casing 7 within which is disposed a magnetizablestructure comprising pole pieces 8 forming with a core 9 a flux gapwithin which the aforesaid coil 4' is received for vibratory movement,the field in said flux gap being produced by a current traversing a coil10 which magnetically coacts with the pole piece 8 and the core 9. Thecasing 7 is flared outwardly and, at its outer end, comprises a flangededge 7a for the reception of the outer edge of the ring 5 andthe washers6 carried thereby, the latter being securely maintained in the positionillustrated by a ring 11 suitably secured to the flange 7 a andoverlying the washers 6.

In operation, a relatively heavy current traverses the coil 10 andproduces a relatively intense magnetic field in the flux gap in which isreceived the coil 4:. As stated, the latter is traversed by a currentvarying in accordance with the sound to be reproduced. and the varyingmagnetic field thus set up by the coil 4 reacts with the magnetic fieldin the flux gap to produce corresponding vibration of the compositediaphragm formed by the attached sections A and A1. Due to the provisionof the corrugations 1 on the section A and the corrugations 2 on thesection Al, the composite diaphragm tends to and does substantiallyretain its cone-shaped configuration. Accordingly, the formation oflocal vibrations in different areas or regions of the compositediaphragm is impended or substantially prevented and, as stated, theabsence of such local vibrations is strongly conducive to thefaithfulness of sound reproduction.

The diaphragm structures or sections A and A1 may be formed from anysuitable material such, for example, as thin metal, impregnated clothor, and' preferably, paper.

The thickness of such diaphragm-forming material may be such as issuitable and desirable although ordinarily the thickness of saidmaterial is of the order of 2, 3 or 4 mils, more or less.

The various corrugations may be formed in the structures or sections Aand A1 in any Way that may be suitable or desirable. Thus, saidcorrugations may be formed while said members are plane and flat and,hence, before they have beenbroughtto their frustro-conicalconfiguration. Ordinarily, however, it is unsatisfactory to corrugatethemember A while it isffplane and flat and to bring it then to itsfrustro-conical configuration. Furthermore, and if desired, the group ofcorrugations may be formed after said sections A and A1 have beenbrought to the configuration last noted. Moreover, if desirable, thesections A and/or A. may be entirely uncorrugated, the proper strengthor reinforcement being added thereto by separate rib structures whichare applied to the section A circumferentially thereof and to thesection A1 axially thereof.

The corrugations 1 may be suitably spaced along the surface of thesection A. Thus, for example, there may be from 3 to 5 corrugations perlinear inch. Similarly, the corrugations 2 on the member A1 may besuitably spaced. Thus, for example, there may be from 2 to 3corrugations for each arcuate inch along the periphery of the larger endof said section A1. Furthermore, the radius or depth of the corrugations1 and 2 may be such as is suitable or desirable, as for example, of aninch, more or less.

Although the specific description of my invention relates to a diaphragmwhich is frustro-conical and formed. of frustro-conical sections itshall be understood that my tendin and secured between said sectionsinvention is not to be thus limited. Thus, for at the ase of the cone.

example, said diaphragm-forming sections may be pyramidal orhemispherical. Still further, it shall be understood that my inventionis not to be limited to a diaphragm forming a hollowhgeometrical figurefor, ob-

the principle of my invention is ap= viously,

to plane flat diaphragms, and other plicable types.

In this specification and in the appended claims, the expressionintegral corrugations e-shall'be understood as defining corrugationsformed by action directly on the material forming the diaphragm sectionsand the term corrugations shall be understood as generic and definingnot only the aforeanother,

said integral corrugations but those comprehending separate ribstructures, as above 1 described What I claim is:

1. A laminated diaphragm having the configuration of a hollowgeometrical figure, said diaphragm comprising attached complementalsections of sheet material disposed one within another, said sectionshaving corrugated surfaces.

2. A diaphragm having the configuration of a hollow frustro-conicalfigure, said dia phragm comprising attached complemental sections ofsheet material disposed one within another, one of said sections havingcircularv corrugations and another of said sections being provided withcorrugations angularly disposed with respect to said first named corruations.

3. diaphragm having the configuration of a hollow frustro-conicalfigure, saiddiaphragm comprising attached complemental sections of sheetmaterial disposed one within one of said sections having circularcorrugations and another of said sections being provided with integralcorrugations angularly disposed with respect to said first named corruations. v

4. A diap ragm having frustro-conical shape and comprising complementalsections fitting one within another anisecured together, one of saidsections being circularly corrugated and another of said sections hav-6. A diaphragm of frustro-conical shape comprising complementalfrustro-conical sections, one fitting within another and saidsectionsbeing secured together, one of said sections having corru ations lyingin planes normal to the axis 0 the cone and another of said sectionshaving corrugations lyingm planes radial to the mg corrugations in thesurfaces thereof which extend in different directions.

In testimony whereof I have signed this specification this 14th day ofJanuary, 1929.

RUDOLPH F. MALLINA.

extending flange se-.

ing corrugations lying in planes radial to the diaphragm, alternatecorrugations of said last named section being shorter than the othercorrugations thereof.

5. A diaphragm of frustro-conical shape comprising complemental sectionsone fitting within another, said sections being secured together, one ofsaid sections having corrugations extending circularly in planes normalto the axis of the cone and another of said sections having corrugationsextending in planes radial to the cone, and a flexible annularsupporting member for the diaphragm having a portion of its innerperiphery ex-

